The objective of the study is to utilize sinusoidal distention to examine the hitherto uncharacterized dynamic mechanical properties of the human colon in vivo. The specific aims of the study are to define the dynamic mechanical properties of the colon in 20 healthy volunteers by applying sinusoidal strains (volume distensions) at different rates and prestress (baseline volume); to measure the cycle to cycle variability in pressure output in response to sinusoidal volume oscillations and to characterize the time course of this variability; to examine within cycle variation in pressure response during steady state oscillations; and to characterize the steady state dynamic mechanical properties of the colon in terms of a dynamic elastance, tissue resistance, and tissue hystersivity and to define their frequency and pre-stress dependence.